Birthday Stars

Astronomers measure distances to the stars in terms of light years, units that combine time and distance. One light year is the distance light travels in one year; so if you look at a star ten light years from Earth, the light you see from it left ten years ago and is therefore ten years old.

To see starlight that's your age—or the age of a friend or family member—use the table below. When you've found the star whose light is the right age, you can:

Copy its name and paste it into our star chart to find its location in the sky. If it's a bright star, you might try to find it by printing the star chart, making a red-light, night-vision flashlight, and heading outside. If it's dim, you may need a telescope. Try going to a star party or public observatory and ask the astronomers to show it to you. (Visit our Local Societies page to find local amateur astronomers.)

Find out more about it by going to STARS—a web site by an astronomer devoted to the bright stars.

The table below lists:

The age of the person whose star you're looking for.

The star's name. Stars can have several names, ranging from Arabic or Greek proper names for the brightest stars (such as Sirius) to various catalog numbers. The names used in this column work best for locating the star using the "find" command on digital star charts. Stars used to be named in order of brightness within a given constellation in order of their brightness, with Alpha being the brightest, Beta the second-brightest, and so on. (In this system, the constellation name is given with the Latin genitive case; so the brightest star in Orion is Alpha Orionis or Alpha Ori.) Early estimates of which star is brightest were based on visual observations alone and often proved to be flawed, but the naming system is still widely employed.

The star's precise distance, in light years.

The star's apparent magnitude ("Mag."), a measure of its brightness as seen from Earth. (In this system, the numbers get larger as the stars get dimmer. Bright stars are of magnitude 0, 1, or 2, while the dimmest stars generally visible with unaided eyes are of about magnitude 6.) Stars in this table with magnitudes dimmer than about 6 can only be viewed with binoculars or a telescope. Exceptionally bright stars have negative magnitudes (such as Sirius, the brightest star in our skies, mag. -1.4.) A star's apparent magnitude—how bright it looks to us—results from both its actual light output and its distance from Earth—so an inherently brilliant star that is far from Earth will look dim in the sky, while an ordinary star nearby will look bright (which is the case for the Sun!).

Comments. Here we give a bit more information on each star (including the name of the constellation, or star pattern, in which it is located, and its location, referenced in compass directions (N, S, E, W) and degrees ("deg.") on the sky. To estimate degrees of angle in the sky ("deg." in our comments table), consider that your fist at arm's length takes up about 10 degrees of the sky, while the full Moon is about half a degree wide.

Most of the stars in this table can be seen from Earth's northern hemisphere with the naked eye. Exceptions, listed in italics, are those either too dim to see without binoculars or a telescope (check their magnitudes and note it is higher than 6) or too far south to be seen from most locations in the northern hemisphere.

Birthday Star ChartNote: Stars listed in italics are too dim to see by naked eye.

Your Age

Star

Distance (light years)

Magnitude

Comments

0

Sun

(8 light-minutes)

-26.7

The "birthday star" for babies born today is the Sun!

4

Alpha Centauri

4.4

0

Nearest known star to the Sun; actually part of a triple star system; bright, but too far south to be seen from North America

6

Barnard's Star

6

5.9

E. E. Barnard discovered that this star is speeding toward the Sun; it will become the nearest star to us in 10,000 years

8

Wolf 359

7.8

13.4

Very faint dwarf in Leo, the Lion; visible with a medium-sized telescope

Blue-white giant, 120 times as luminous as the Sun; brightest star in Leo

78

Mizar

78.2

2.2

Naked-eye double star with its partner, the fainter Alcor, and itself a telescopic double; in Ursa Major, at the crook of the Big Dipper's handle

79

SAO1002

78.6

10.4

Double star in Camelopardalis, the Giraffe; requires a telescope

80

7 And

79.9

4.5

One star among many in the rich star clouds of the Milky Way, in Andromeda

81

Alioth

80.9

1.8

The "bright eye" in the Big Dipper's handle, immediately W of Mizar and Alcor

82

Beta Oph

81.9

2.8

Pale yellow; good in binoculars

83

Zeta Aql

83.3

3

Tip of Aquila the Eagle's West wing

84

Sabik

84.1

2.4

White star E of Scorpius, in the ecliptic near the Milky Way

85

Seginus

85.2

3

Just under 10 deg. N of Arcturus

86

Tau3 Eri

86.2

4.1

SW of Orion, in Eridanus, the River

87

Algorab

87.9

2.9

At the NE corner of Corvus, the Crow

88

Epsilon Cet

88.2

4.8

In Cetus, the Whale, 10 deg. SE of Mira

89

Ascella

89.1

2.6

Bright enough to stand out against the rich star clouds of the central Milky Way; in eastern Sagittarius, the Archer.

90

15 Peg

90.2

5.5

In Pegasus, on the E edge of the Milky Way's glowing river of stars

91

38 Gem

91.1

4.7

In Gemini, all but lost amid Milky Way star clouds

92

Omega And

92.3

4.8

Look 9 deg. NE of the Andromeda galaxy

93

Algol

92.8

2.1

The most famous variable star in the sky; an "eclipsing binary" that dips in brightness, from mag. 2.1 to mag. 3.4, when the primary star is partly eclipsed by its dimmer companion. In Perseus, 18 deg. NNE of the Pleiades star cluster.

94

Lambda Gem

94.3

3.6

Variable star of the Cepheid type, which can be used to measure distances; in Gemini, at the right knee of the eastern Twin

95

Gamma Oph

94.8

3.75

In Ophiuchus, 18 deg. NW of the Wild Duck star cluster (M11)

96

Diphda

95.8

2

A yellow star near the ecliptic in Cetus, the whale

97

Alpheratz

97.1

2.1

NE corner of the "Great Square" linking Andromeda and Pegasus; spectrum displays "weather" in form of sulfur clouds on its surface

98

SAO141665

98

4.5

In central Ophiuchus

99

Nu1 Dra

99.9

4.9

Part of a telescopic double star in Draco, the Dragon

100

Nu2 Dra

99.9

4.9

The other member of this pretty pair of white stars (see 99)

101

Alkaid

100.7

1.85

White star at the tip of the Big Dipper's handle

Some Comments on the Chart

Looking over the chart, you may have noticed that it's missing entries for several ages—notably 2, 3, 5, and 7—and that our entry for age 6, Barnard's Star, is too dim to be seen without a telescope. But at greater distances there's a bright star for nearly every age. What's up with that? The reason is that as we go out farther, we're sampling steeply larger volumes of space, and therefore have more stars to choose from. (The volume goes up as 4/3?R3, where ? = 3.14 and R is the distance, meaning the radius of the sphere in which we are searching.) In cases where we had several options, we have picked the brightest star visible from northern latitudes, where most—though by no means all!—observers dwell.

Certain commercial concerns offer to "name" stars for individuals—at a price. These star "registries" have no official sanction. Astronomical objects are named by the International Astronomical Union, according to internationally agreed-upon protocols which do not permit naming stars for living persons. Stars rarely get names these days, but catalog numbers But while you cannot legitimately name a star for yourself or a friend or family member, we invite you to observe a star whose light is as old as you are, or they are, and to possess a photo of it if you like. Like the night sky, it's free!

Our list of Birthday Stars is based on a book project of that title initiated by Timothy Ferris in 1997. For another approach, visit the Joint Astronomy Center in Hawaii.